BOZEMAN – Mixed species cover crops, also known as cover crop “cocktails,” are the focus of a study by researchers at Montana State University and will be the topic of a field tour on July 8 from 9-11 a.m., near Conrad, Montana.

The four-year study, funded by the U.S. Department of Agriculture’s Western Sustainable Agriculture Research and Education, or WSARE, is a collaborative project with Montana producers to look at cover crop mixtures as a partial replacement of fallow in rain-fed cropping systems.

Growers have expressed interest in using cover crops to improve soil health. Cover crops increase soil organic matter, which improves water holding capacity and nutrient availability and they provide other potential benefits such as reduced erosion.

Until recently, the focus of cover-crop research has been on single species legume cover crops as a soil-building tool.

“A goal of this study is to find out whether mixed cover crops add any benefits beyond those provided by legume monocultures, and what works and does not work well for our production systems,” said Clain Jones, Extension soil fertility specialist at MSU.

Seed mixes being tested contain species from various groups and are being compared with fallow and a single-species legume cover crop. The groups were selected to address soil-quality issues specific to farming in the northern Great Plains. They include species that fix nitrogen to reduce nitrogen fertilizer inputs, provide ground cover to reduce weed establishment and evaporation, have deep tap roots to minimize compaction and help water infiltrate, or have fibrous and extensive root systems to increase organic matter and promote aggregation.

The field tour will be on land leased by Herb Oehlke, one of several farmers assisting with this study. Oehlke has produced primarily wheat and barley on his dryland, no-till operation. He has been experimenting with a diversity of cover crop mixes for six years to improve soil health, eliminate a hard-pan layer and reduce the use of commercial fertilizer and herbicides.

The field tour is sponsored by the National Center for Appropriate Technology, the USDA Risk Management Agency and MSU Department of Land Resources and Environmental Sciences (LRES).

Researchers Clain Jones, Perry Miller and Cathy Zabinski, all from LRES, will present the benefits and challenges of cover crops and describe what they have learned so far. Herb Oehlke will discuss his cover crop experiences. Jane Holzer will describe a cover crop cocktail demonstration project spearheaded by local conservation districts and the Montana Salinity Control Association. Jeff Schahczenski of NCAT will be discussing a new cover crop termination date policy as it relates to crop insurance issues.

There will be question-and-answer sessions and two cover crop/soil health sites will be available for viewing following this tour. Refreshments will be provided by the Pondera County Conservation District and Montana Salinity Control Association. The field tour is free and open to the public, however, please pre-register by July 3 at https://www.ncat.org/tours/, or call Jeff Schahczenski at (406) 494-8636 for details. If you have questions about the study, please contact Clain Jones (406) 994-6076 or clainj@montana.edu.